Disc drive systems can be used for storage of digital information that can be recorded on concentric tracks of a magnetic disc medium. Several discs are rotatably mounted on a spindle, and the information, which can be stored in the form of magnetic transitions within the discs using a writer, is accessed using a reader. The reader and/or writer is carried by a slider that is located on an actuator arm that moves radially over the surface of the disc. The slider and transducer can be collectively referred to as a magnetic head.
The discs can be rotated at high speeds during operation. As the discs are spun, the slider and the reader and/or writer glide above the surface of the disc on a small cushion of air. Upon reaching a predetermined high rotational speed, the head floats in air at a predetermined distance from the surface of the disc where it is maintained during reading and recording operations. To maximize this high areal recording density, the flying height (i.e., the distance between the head and the surface of the disc as the head floats above the surface) can be minimized.
One or both of the air bearing surfaces of the head and the disc can be coated with a diamond like carbon (DLC) protective overcoat and/or a lubricant layer. The function of the DLC overcoat is to protect underlying metals and alloys from wear and corrosion during the manufacturing process and throughout the lifetime of the disc drive system. As applied to the head, the DLC overcoat can include a DLC overcoat and an adhesion layer. DLC overcoat thickness for the head can range from about 10 to 20 angstroms, while typical values of DLC overcoats for magnetic media can be in excess of 20 Angstroms. DLC overcoat thicknesses is one of the biggest contributors to head media separation (HMS) distance. The HMS distance is measured from the magnetic surface of the head to the magnetic surface of the media. The HMS distance in turn affects the data reading and writing efficiency of the transducer.